DIY: Minimum Window Subsequence

Solve the interview question "Minimum Window Subsequence" in this lesson.

Problem statement

Given strings ss and tt, find the minimum (contiguous) substring ww of ss, so that tt is a subsequence of ww.

If there is no window in ss that covers all characters in tt, return an empty string "". If there are multiple minimum-length windows, return the one with the left-most starting index.


The input will be two strings ss and tt. The following is an example input:

ss = "abcdebdde"
tt = "bde"


For the above input, the output will be:


The strings "bcde" and "bdde" are both minimum subsequences, but "bcde" occurs before "bdde".

Coding exercise

For this coding exercise, you need to implement the min_window(ss, tt) function, where ss and tt are the provided strings. The function should return the minimum subsequence of tt that exists in ss.

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